The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Known powertrain architectures include torque-generative devices that generate and transfer torque via a torque transmission device to a driveline including one or more drive wheels for traction to propel a vehicle. Torque-generative devices may include an internal combustion engine and/or other machine(s) not utilizing internal combustion as an energy source. The other non-internal combustion energy sources may include stored electric energy, stored hydraulic energy, and stored pneumatic energy to generate tractive torque. Electric machine(s) may utilize stored electric energy to create torque. Additionally, electric machine(s) may transform vehicle kinetic energy that is transmitted through the drive wheels to energy that is storable in an energy storage device.
Known hybrid powertrain architectures may include an engine crankshaft rotatably coupled to an electric machine via a mechanical coupler in a fixed ratio. The engine, electric machine and mechanical coupler can be arranged in a belt-alternator-starter (BAS) configuration. During deceleration events, the electric machine can capture regenerative energy through negative torque applied to the vehicle's axles and an electrical energy storage device can store the regenerative energy. It is known to limit the maximum capability of the electric machine to capture regenerative energy associated with a highest transmission gear state in order to maintain a constant vehicle deceleration rate and avoid unacceptable changes in the vehicle deceleration rate when utilizing the maximum capability of the electric machine to capture regenerative energy associated with lower transmission gear states. As a result, hybrid powertrain architectures arranged in the BAS configuration may not fully utilize the maximum capability of the electric machine when in the lower transmission gear states in order to maintain a constant vehicle deceleration rate.